Over the past several years, sensor technology has evolved in an isolated manner, with individual components becoming smaller, less costly to build, more sophisticated and specialized. This has led to a proliferation of singular devices that perform exceptionally well at their individual purpose. It is clear that the next wave of development will be in the integration of components into systems or sensor suites, which far transcend the capability and intent of the individual components.
The concept behind the Seamless Sensory System (3S) is to integrate those components and technologies that, in essence, complete the picture beyond the individual contributions. The word, Seamless, is carefully chosen. It is intended to indicate the complementary nature of the underlying sensors. Seamless in its capabilities, through such natural transitions as, outdoor to indoor, day to night, cold to warm; Seamless in its capabilities through changes in surrounding conditions such as transmission denial and human sensory deprivation.
The Seamless Sensory System (3S) core technology is created by a data fusion of an Ultrasonic Doppler Velocity Measurement (UVM) sensor and Inertial Measurement Unit (IMU). The result is a comprehensive and seamless data set of positioning information, independent of the users surroundings. Position is determined in the open, in cities, in buildings, subterranean locations and in overhead vegetation cover/canopy.
The methodology of the invention is based on non-traditional strap down navigation technology. The recent introduction of Commercial of the Shelf (COTS) low cost, low power, small size Inertial Measurement Unit (IMU) products afford the consideration of a combined IMU/UVM technology. While the integration of GPS/IMU has been accomplished as seen in U.S. Pat. No. 6,522,266 the prior state of the art lacks the essential precision velocity ‘motion’ measurement of the navigator. The integration of a comprehensive UVM/IMU overcomes the drawbacks of previous inventions.
The invention's design is that of a small lightweight, affordable product. The accuracy of such a system is made possible based on innovations arising from research and development of a unique integration of IMU/UVM initialized with GPS. The results show that integration of small size high accuracy GPS technology and low cost, low power, and small size Micro Electro Mechanical System (MEMS)/Fiber Optic Gyros (FOG) IMU or equivalent, and Ultrasonic Velocity Measurement (UVM) technology provides accurate positioning. While an IMU is incorporated to the invention, the use of new and yet to be created inertial technology is a “plug and play” component to the invention.
The Ultrasonic Doppler Velocity Measurement (UVM) Sensor is an essential component to the invention's ability to enable “GPS like performance” under any environment, including GPS DENIED CONDITIONS. This component of the invention uses ultrasonic Doppler signals to determine precise ‘motion’ velocity information of the user.
The invention provides position information in areas devoid of traditional GPS signal coverage. The invention can use its GPS/IMU integration in concert with static updating techniques during loss of GPS signal. This is done by the use of Zero Velocity (ZUPT) and Fixed Coordinate Calibration. This methodology takes full advantage of attributes germane to personal navigation. Key to leveraging the benefit of human dynamics is the location of the ‘motion’ sensor(s) at a select location relative to the human body, which affords the lowest dynamics of motion during normal human locomotion.
In addition the dynamics of human locomotion naturally support the static and near static updating techniques implemented by the invention. When combat or other conditions suppress the luxury of performing these updates, the invention further utilizes the Ultrasonic Doppler Velocity Measurement (UVM) Sensor to continue positioning performance in battlefield and other GPS denied conditions.